From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 96FE3297A71; Fri, 23 May 2025 17:23:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748020988; cv=none; b=cLmyrRLP4cbklIvKXI9qnN/gC7wwwOcIGS4puMa/R9tl7bCwHdnF83zC3jaZWyrW8GyCeDPTB0RIS+1P5u1pqSwG3GQ2AKlbuyo6FfJOUE3XGjG9xx72Xk0FpjGZm11gy8BJel7hRRALzre4LeTa32Sp3p25Y5f9Vi9/tYT9ILo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748020988; c=relaxed/simple; bh=NUvbc6H+63QwbLHlhk9ScPPC6XeQK+9ekKzWJM7gBxI=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=JmYq0HlhH+vmUgUXVPWkM8azCnTP4G6KRA6zxxbVwryRe8b4OhkTsCIvzaw4opliMIjPGLuq/dbskWXdoSPM9OmYSGlTRPSN7LK/SPnWobbLFe59TDFIFjrFejLryhiTVaof+bCtI0SvPxGsQ0VILkjE9jdA/piltvArpPDI1+w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Q6judB9i; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Q6judB9i" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D466AC4CEE9; Fri, 23 May 2025 17:23:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1748020988; bh=NUvbc6H+63QwbLHlhk9ScPPC6XeQK+9ekKzWJM7gBxI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Q6judB9iBxgyeVnV6AglZMnfWJRVmqj8bnQ3XfIfutH/CFnB0Ytq8OpY7yrzsITKw 4w/+++NZ37QXH+vjnvQSmXgEwJhIVcBj0ybcoyzIP4CsyvWVxBRBvZkQNLaqhNMdsM pUGB/jlrsiEUm2QvwVqg3T24lA2+RmYfMW2t4CuziLLZGZlVFng9wXtN2mAtht8YiN 1SXnunl7LsIb2Z0DXfYxveTP5KVIZ7aP3FJ6WhCjDbTIuKhkThrzfsG44ceJhInObq EhzMCOtrq9tWwM5X7YVSciVszwjhHTUy/UiYYC+1tNTXOa1oxSEhpM0twVP2Qjomh1 zgdNJ91cFcnoQ== From: SeongJae Park To: SeongJae Park Cc: Baolin Wang , akpm@linux-foundation.org, david@redhat.com, shakeelb@google.com, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, vbabka@suse.cz, rppt@kernel.org, surenb@google.com, mhocko@suse.com, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH] mm: fix the inaccurate memory statistics issue for users Date: Fri, 23 May 2025 10:23:05 -0700 Message-Id: <20250523172305.57843-1-sj@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250523172029.57745-1-sj@kernel.org> References: Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit On Fri, 23 May 2025 10:20:29 -0700 SeongJae Park wrote: > On Fri, 23 May 2025 11:16:13 +0800 Baolin Wang wrote: > > > On some large machines with a high number of CPUs running a 64K kernel, > > What does 64K kernel means? > > > we found that the 'RES' field is always 0 displayed by the top command > > for some processes, which will cause a lot of confusion for users. > > > > PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND > > 875525 root 20 0 12480 0 0 R 0.3 0.0 0:00.08 top > > 1 root 20 0 172800 0 0 S 0.0 0.0 0:04.52 systemd > > > > The main reason is that the batch size of the percpu counter is quite large > > on these machines, caching a significant percpu value, since converting mm's > > rss stats into percpu_counter by commit f1a7941243c1 ("mm: convert mm's rss > > stats into percpu_counter"). Forgot asking this, sorry. Should we add Fixes: tag and Cc stable@? Thanks, SJ [...]